Paleoclimatic record of the past 22,000 years in Venice (Northern Italy): Biostratigraphic evidence and chronology

Four new 20-m cores drilled (2000–2001) in the historical city centre of Venice, provided new data on Late Pleistocene and Holocene deposits from pollen biostratigraphy, foraminiferal associations and 10 new 14C dates. About 22,000 years ago, alluvial deposits were laid down in an environment characterized by intense flooding with episodes of swamp conditions between 22,410±130 and 20,830±130 years BP. This full glacial phase was followed by one of prevailing fine materials between 19,790±120 and 19,280±120 years BP. The Flandrian marine invasion occurred 5520±50 years BP, and gave rise to a layer about 5 m thick, in which the foraminiferal associations show ancient channels and buried salt marshes. Palynological analysis indicates two different pollen zones: one is full glacial, with two phases of climatic warming going back to the Tursac and Laugerie interstages; the second corresponds to Holocene lagoonal deposits. The main peat layers represent episodes of stagnation in stadial conditions. The two warm interstages lasted a few centuries. Above the Laugerie interstage, peaty remains in continental sands underlying the Holocene lagoonal deposits of Atlantic age date back to 9173±80–7165±60 years BP, showing the presence of the Early Holocene.